From the Rolls-Royce experimental archive: a quarter of a million communications from Rolls-Royce, 1906 to 1960's. Documents from the Sir Henry Royce Memorial Foundation (SHRMF).
Table of measurements detailing the movement of a bellows unit under various conditions.
| Identifier | ExFiles\Box 156\2\ scan0044 | |
| Date | 18th March 1938 guessed | |
| (1) Bellows unit fixed in casing with no valve head fitted, i.e. on cold stop. (3) Bellows unit in casing with valve fitted - i.e. set at correct opening temp. (3) Bellows unit in casing after 450 miles running with charge released - free position. (4) Bellows unit in casing after 450 miles running with charge released - bellows lift to maximum travel so that bellows top plate is touching bypass seating. Movement from cold stop. 0 .156 .323 .453. | ||